Popular scented products — including those claiming to be "green" — emit chemicals not listed on the label, including some considered toxic and possibly carcinogenic, a study says.

Each of the 25 tested products emitted at least one chemical classified as toxic or hazardous under federal law and 11 gave off at least one listed as a probable carcinogen by the Environmental Protection Agency, according to the study published online this week in the journal Environmental Impact Assessment Review.

"This is a big untold story," says lead author Anne Steinemann, a professor of civil and environmental engineering at the University of Washington. She says her study is the first to look at fragranced products.

The products emitted a total of 133 chemicals, about 17 each. But only ethanol was listed on labels. Manufacturers are not required to list ingredients in fragrances; a pending Senate bill would require it.

Half of the products tested made claims about being "green, organic or natural," but "they emitted just as many toxic chemicals," Steinemann says.

The study analyzed top-selling air fresheners, laundry products including detergents, personal-care products such as soaps and cleaning products. It does not disclose the brand names. "We don't want to give people the impression that if we reported on product 'A' and they buy product 'B,' they're safe," says Steinemann, who led a team from the University of Washington-Seattle and Battelle Memorial Institute in Columbus, Ohio. "The whole class is problematic."

The researchers placed a sample of each product in a closed glass container at room temperature and tested the air for volatile organic compounds. Because product formulations are proprietary, they couldn't determine whether a chemical came from the product base, the added fragrance, or both.

The most common chemical was citrus-scented limonene, which Steinemann says can mix with air to create formaldehyde. Also emitted from at least half were three chemicals classified as toxic: pine-smelling alpha-pinene; ethanol; and acetone, a solvent in nail polish remover.

"Yes, it's low-level exposure, but low levels add up," she says, adding the EPA sets no safe limit for many of the chemicals detected.

The International Fragrance Association North America says that the report "unnecessarily alarms the public with insinuations of danger." It says most materials can be toxic in high concentrations.

The study does not discuss health effects, but two national surveys last year by Steinemann found 20% of people reported health problems from air fresheners; 10% from laundry products. Complaints were twice as common in people with asthma.

She suggest consumers clean with vinegar and baking soda, open windows for ventilation and use unscented products. — Wendy Koch